The invention falls within the field of polymer (“plastic”) bags that include handles, and particularly those bags in which the handles are formed by cutting an opening in the bag material near the top edge of the bag, and typically using a die cutting technique. Within this general bag design, there are circumstances in which the weight of the bag contents against the bag handles is disproportional; i.e., the walls of the bag are of sufficient strength (usually expressed as gauge or thickness) to hold the contents, but not sufficient to bear the entire weight at the die cut handles.
Conventional solutions to this problem exist but the most common are to use a heavier gauge of plastic for the entire bag; to add separate, stronger handles to the bag; or to reinforce the die cut handles, but not the entire bag.
Using a heavier gauge of plastic is less cost-effective whenever the contents portion of the bag doesn't require the same gauge as the handles.
Adding separate handles requires one or more extra manufacturing steps (as compared to die cut openings) and thus increases complexity and cost.
Reinforcing the bag at the handles is also helpful, and can be done with patches (usually rectangular) of extra plastic or some other material fixed to the inner faces of the bag at the position through which the die cut handles are opened. The patch structure has the cost advantage of minimizing the amount of extra material required, but also adds another manufacturing step.
Zipper closure bags are also well-established in the art and such bags can be formed with certain types of handles. In particular, a press-to-close zipper is typically added as a narrow ribbon in which the male and female profiles of the zipper are fastened together. Each respective profile is secured to one of the respective adjacent layers of the moving polymer film that is the precursor of the eventual finished bags.
Conventionally, the zipper must remain closed throughout the manufacture of the entire bag, because if a zipper is opened while the polymer sheet is in precursor form, the zipper may be difficult or impossible to re-close in an appropriate manner, and will thus prevent the manufacture of properly finished bags.
Adding reinforcing handle patches to the interior surface of the rolling plastic bag stock that already includes a press-to-close zipper is conventionally unknown. In particular, adding the patches requires that the layers of film be separated so that the patches can be first inserted and then heat welded to the film layers. Such a separation step is, however, incongruent with the requirement that the zipper profiles remain closed.
Thus, plastic bags that include both a press-to-close zipper and a reinforced die cut handle above the zipper are simply unavailable.